Hexagonal Perovskites: Atomic Structure of the Initial Nucleation Layer in Hexagonal Perovskite BaRuO
            3
            Thin Films (Adv. Mater. Interfaces 7/2021)

STEM coupled with the optical system was used for the investigation of the early oxidation on the surface of Cr. Cr thin films (30 – 1000Å) were prepared by evaporation onto the polished or air-cleaved NaCl substrates at room temperature and 45°C in a vacuum of 10−6 Torr with an evaporation speed 0.3Å/sec. Rather thick specimens (200 – 1000Å) with various preferred orientations were used for the investigation of the oxidation at moderately high temperature (600 − 1100°C). Selected area diffraction patterns in these specimens are usually very much complicated by the existence of the different kinds of oxides and their multiple twinning. The determination of the epitaxial orientation relationship of the oxides formed on the Cr surface was made possible by intensive use of the optical system and microdiffraction techniques. Prior to the formation of the known rhombohedral Cr2O3, a thin spinel oxide, probably analogous to γ -Al203 or γ -Fe203, was formed. Fig. 1a shows the distinct epitaxial growth of the spinel (001) as well as the rhombohedral (125) on the well-oriented Cr(001) surface. In the case of the Cr specimen with the (001) preferred orientation (Fig. 1b), the rings explainable by spinel structure appeared as well as the well defined epitaxial spots of the spinel (001). The microdif fraction from 20A areas (Fig. 2a) clearly shows the same pattern as Fig. Ia with the weaker oxide spots among the more intense Cr spots, indicating that the thickness of the oxide is much less than that of Cr. The rhombohedral Cr2O3 was nucleated preferably at the Cr(011) sites provided by the polycrystalline nature of the present specimens with the relation Cr2O3 (001)//Cr(011), and by further oxidation it grew into full coverage of the rest of the Cr surface with the orientation determined by the initial nucleation.

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Atomic structure of [0001]-tilt grain boundaries in ZnO: A high-resolution TEM study of fiber-textured thin films

Physical Review B ◽

10.1103/physrevb.70.125415 ◽

2004 ◽

Vol 70 (12) ◽

Cited By ~ 53

Author(s):

Fumiyasu Oba ◽

Hiromichi Ohta ◽

Yukio Sato ◽

Hideo Hosono ◽

Takahisa Yamamoto ◽

...

Keyword(s):

Thin Films ◽

High Resolution ◽

Grain Boundaries ◽

Atomic Structure ◽

High Resolution Tem

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EXAFS spectroscopy study of the atomic structure of ZnS nanocomposite thin films

Journal of Structural Chemistry ◽

10.1134/s0022476611070249 ◽

2011 ◽

Vol 52 (S1) ◽

pp. 181-185 ◽

Cited By ~ 3

Author(s):

R. G. Valeev ◽

A. N. Beltukov ◽

F. Z. Gilmutdinov ◽

É. A. Romanov ◽

A. N. Deev ◽

...

Keyword(s):

Thin Films ◽

Atomic Structure ◽

Exafs Spectroscopy ◽

Spectroscopy Study ◽

Nanocomposite Thin Films

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The atomic structure of growth interfaces in Y–Ba–Cu–O thin films

Journal of Materials Research ◽

10.1557/jmr.1991.2264 ◽

1991 ◽

Vol 6 (11) ◽

pp. 2264-2271 ◽

Cited By ~ 56

Author(s):

R. Ramesh ◽

A. Inam ◽

D.M. Hwang ◽

T.S. Ravi ◽

T. Sands ◽

...

Keyword(s):

Thin Films ◽

Atomic Structure ◽

Film Growth ◽

Substrate Surface ◽

Oriented Growth ◽

Surface Steps ◽

Nucleation Sites ◽

Oriented Films ◽

Second Phases ◽

Ledge Mechanism

We have examined the atomic structure of growth interfaces in thin films of Y–Ba–Cu–O grown on [001] perovskite or cubic substrates. At substrate heater temperatures in the range of 780–820 °C c-axis oriented growth is observed on these substrates. On SrTiO3, the first layer appears to be either a BaO or a CuO2 plane while on LaAlO3 the first layer appears to be a CuO chain layer. The mismatch on the a-b plane is accommodated by the formation of interface dislocations. Defects on the substrate surface propagate as defects in the film. These defects are primarily translational boundaries and in some cases second phases. At lower substrate heater temperatures, i.e., 650–700 °C, a, b-axis growth dominates. Defects and steps on the substrate surface are more detrimental in the growth of a, b-axis oriented films, since they tend to favor the nucleation of c-axis oriented domains. This is ascribed to the ledge mechanism of c-axis film growth, for which the surface steps are good nucleation sites.

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